Investigation on the meta-dynamic recrystallization behavior of Inconel 718 superalloy in the presence of δ phase through a modified cellular automaton model

The Meta-dynamic recrystallization (MDRX) behavior of Inconel 718 superalloy containing second phase particles (δ phase) was investigated through the isothermal two-stage compression deformation tests under the deformation temperatures of 960–1000 °C,the strain rates of 0.01, 0.1, 1, 5s⁻¹ afterwards to the strain of 0.2, holding time of 0s, 10s, 20 s at the deformation temperature, and then to the accumulated strain of 0.4. A developed cellular automaton (CA) model was built to better describe the MDRX process, with both considering the δ phase particles effects of particle stimulated nucleation (PSN) and pinning MDRX grain growth. The reasonable functions of driving force and nucleation rate were developed for predicting the MDRX process during the multi-pass deformation process in the developed CA model. The simulated microstructures indicate a good consistency with the experimental results, which shows the developed CA model could well describe the MDRX process of the studied superalloy. The effects of holding time, strain rate, temperature and δ phase on MDRX were analysed and discussed through the developed CA model.